DM1 is the most frequent genetic myopathy in the adult. Actually there is no curative treatment, and symptomatic cares are essentials. The respiratory impairment is the main cause of morbid-mortality at these patients. The median of survival of the patients affected by DM1 with respiratory failure is of 59 years. Mechanisms of disease are complex implying a central and a direct impairment of respiratory muscles. These patients can present an alveolar hypoventilation, notably during night, not correlated to the muscular weakness. These patients often present a cognitive impairment complicating the interpretation of the clinical symptoms and their compliance to treatments. International recommendations for launching mechanical ventilation in neuromuscular diseases are the presence: 1) at least a clinical sign of alveolar hypoventilation, and one of the following criteria 2) diurnal hypercapnia (> 45 mmHg), 3) restrictive syndrome (vital capacity < 50 % and\or maximal inspiratory pressure < 60 cmH20), 4) the existence of a oxygen night-desaturation (SaO2 < 88 %) of more than 5 minutes. However, a Cochrane meta analyzes underline the absence of randomised study estimating the profit risk in the long term of the night-mechanical ventilation for progressive myopathies such as the DM1. The validity of these criteria and the effect of the ventilation on the survival and the complications were never estimated in DM1. On a retrospective series, the compliance is inferior and the observance is only 20 % a year and the incidence of the complications (death or resort to a tracheostomy) was 6 times as important in non observant patients.